Oil burner pump

ABSTRACT

In a variable capacity pump with an inlet port and a discharge outlet adapted for connection to a nozzle, a cylinder within the pump body having a casing and a pump stator slidably mounted in the cylinder and receiving a vaned rotor for receiving fluid from said inlet and discharging to said outlet; the improvement which includes a delivery chamber receiving said pumped fluid with a cut off valve opening. Said opening includes a valve seat with a soft valve in one end of the movable stator normally engaging said seat. A spring retainer is normally spaced outwardly of one end of the stator and a weak air release spring is interposed between said retainer and said stator. A discharge pressure spring is interposed between the pump body and said retainer, normally holding the retainer during initial movement of the stator towards and into engagement with the retainer so that initial low pressure air delivered to said chamber lifts the soft valve from said seat for delivery to said nozzle. Solid liquid subsequently pumped to said chamber of progressively increasing pressure causes the stator to move further radially outward against the action of said discharge pressure spring further opening said valve to reach an equilibrium of volume of pumped liquid delivered to said nozzle. The improved pump includes opposed pairs of intake and outlet grooves upon opposite sides of the stator registerable with corresponding pairs of intake and discharge ports extending through the inner and outer walls of the pump cylinder together with opposed bosses upon opposite sides of said stator normally closing one of each pair of intake and discharge ports whereby, the stator is reversible face to face, depending upon the direction of rotation of the rotor. An improved drive shaft seal is incorporated into the pump body which includes a stationary seal element on the body and a rotative seal element engageable therewith and connected with said drive shaft.

United States Patent [191 DeLancey 1 3,850,548 [451 Nov. 26, 1974 1 1OIL BURNER PUMP [76] Inventor: Warren H. DeLancey, 1580 Prospect Rd.,Apt. 1-1-4, Elyria, Ohio 44035 [22] Filed: Feb. 12, 1973 [21] Appl. No.:331,611

[52] U.S. C1 417/220, 418/31, 417/310 [51] Int. Cl. F04b 49/00 [58]Field of Search 417/310, 213, 219, 220, 417/315, 442, 259; 418/15, 31,39, 97, 100, 26, 24, 25, 27

[56] References Cited UNITED STATES PATENTS 2,291,424 7/1942 Wichorek417/239 2,451,279 10/1948 DeLancey 417/213 2,518,578 8/1950 Tomlinson418/27 2,678,607 5/1954 Hufferd et a1. 417/220 2,746,391 5/1956Jaworowski et a1. 417/239 3,187,676 6/1965 Hartmann 418/31 3,379,0064/1968 Eickman 417/220 Primary Examiner-William L. Freeh Attorney,Agent, or Firm-Cul1en, Settle, Sloman & Cantor [57] ABSTRACT In avariable capacity pump with an inlet port and a discharge outlet adaptedfor connection to a nozzle, a cylinder within the pump body having acasing and a pump stator slidably mounted in the cylinder and receivinga vaned rotor for receiving fluid from said inlet and discharging tosaid outlet; the improvement which includes a delivery chamber receivingsaid pumped fluid with a cut off valve opening. Said opening includes avalve seat with a soft valve in one end of the movable stator normallyengaging said seat.

A spring retainer is normally spaced outwardly of one end of the statorand a weak air release spring is interposed between said retainer andsaid stator. A discharge pressure spring is interposed between the pumpbody and said retainer, normally holding the retainer during initialmovement of the stator towards and into engagement with the retainer sothat initial low pressure air delivered to said chamber lifts the softvalve from said seat for delivery to said nozzle. Solid liquidsubsequently pumped to said chamber of progressively increasing pressurecauses the stator to move further radially outward against the action ofsaid discharge pressure spring further opening said valve to reach anequilibrium of volume of pumped liquid delivered to said nozzle, Theimproved pump includes opposed pairs of intake. and outlet grooves uponopposite sides of the stator registerable with corresponding pairs ofintake and discharge ports extending through the inner and outer wallsof the pump cylinder together with opposed bosses upon opposite sides ofsaid stator normally closing one of each pair of intake and dischargeports whereby, the stator is reversible face to face, depending upon thedirection of rotation of the rotor. An improved drive shaft seal isincorporated into the pump body which includes a stationary seal elementon the body and a rotative seal element engageable therewith andconnected with said drive shaft.

15 Claims, 8 Drawing Figures on BURNER PUMP BACKGROUND OF THE INVENTIONThe present invention is an improvement over my earlier issued US. Pat.No. 2,451,279 issued Oct. 12, 1948 entitled VARIABLE CAPACITY VANE PUMPFOR OIL BURNERS.

Heretofore, in variable capacity pumps, particularly adapted for oilburners, though not limited thereto, and as shown in US. Pat. No.2,451,279, fluid enters and leaves the pump through ports in the endcover at right angles to its movement in the pump. This construction isuniversally employed in oil burner pumps to this day. With the adventofthe high speed oil burners, such porting requires the fluid at inlet andoutlet to accelerate and decelerate twice during its passage through thepump to substantiallyhigh velocities, which in itself, is a measurableincrease of torque requirement.

In present oil burner constructions, the direction of flow through thepump'has not been standardized and the pump manufacturers offer pumpswhich can be driven in either direction. This has, heretofore, requiredmajor changes of pump porting. and internal conduit arrangement.

Heretofore, it has been common practice in face seal constructions tohave a spring which forces one face having a limited movement againstanother face of the seal which is fixed. One of these faces isstationary and the other revolves with the shaft to be sealed. Thespring employed has a thrust in the oppositedirection which must bestablized between a moving and a stationary surface. It has beencustomary to make these surfaces as large as the seal itself which hasroughly doubled the rubbing friction of the seal.

It has been common and universal construction in the past on oil burnerpumps used on the popular so-called high pressure atomizing burners toprevent flow of fluid being pumped going to the nozzle 'until apredetermined and safe atomizing pressure was reached. Likewise, duringoperation when the pump has stopped at the end of an operating cycle,this valve to the nozzle would promptly close. These pressures were suchthat they could only be generated by the pump if it were pumping liquid.There was, however, occasions when there was not sufficient liquid inthe pump, such as at original start or to start after a tank supply hasbeen exhausted, and the burner has ceased operation for want of oil. Itwas, therefore, necessary to prime the burner through a priming plugwhich was often a costly service operation.

BRIEF DESCRIPTION OF THE INVENTION I It is an object of the presentinvention to provide an improved method of porting which increases pumpefficiency. This is accomplished by providing an improved pump slide ormovable stator which is thinned on both sides at inlet and outlet portsto provide access for fluid to the varying spaces provided by the bladesand rotor. Thus, fluid can enter substantially in the direction of theflow through the pump and is discharged in the same direction. There isnone of the violent accelera' tion and deceleration as formally, withconsequent saving of power required to drive the unit.

It is another object to provide in the present variable capacity pump asymmetrically constructed movable stator with passages for inlet anddischarge upon its opposite sides so that for a desired reversal in thedirection of drive, the only change required is to reverse thepositioning of the stator slide fromface to face. There is providedinlet and outlet passages or ports on both sides of the pump statorslide together with port covers upon opposite sides of the stator in theform of bosses over. The proper inlets in the rear pump plate andoutlets on the front plate are covered or uncovered as required. Noother changes are needed, no special parts or machining changes arerequired.

- It is another object to provide an improvedmeans of taking up thespring thrust from the face seals for the drive shaft to greatly reducetorque requirement on such seals. For this purpose, there is provided astationary seal in the pump body which receives the drive shaft andspring biased thereagainst is a nose piece with an annular flangedsurface for sealing engagement therewith and which is movable on thesaid shaft and wherein, a seal drive is mounted upon the shaft in engagement with the nose piece and, the spring forces between the sealdrive and the nose piece maintain the nose piece in contact withthe sealto limited areas, but at the same time, the thrust from the spring maybe transmitted to the drive shaft with means to provide for limitedfriction and thrust take up and wherein, seal drive and the nose piecemay be drivingly connected.

It is another object of the present invention to provide within thedischarge chamber a valve seat assembly which permits the discharge ofinitial air through the conduit to the nozzle at constant low pressureswhile still requiring normal higher adjustable operating pressures whenpumping solid oil. This improvement is also applicable to the fixeddisplacement type of pump where a separate piston type of bypass valvecontrol is employed. It is the purpose of the present invention toprovide a means for discharging the air atrelatively low pressure out ofthe nozzle conduit into the tire box while at the same time, providingthat when oil reaches the pump, the normal adjustable pressure will begenerated.

These and other objects will be seen from the following specificationand claims in conjunction with the appended drawings:

THE DRAWINGS FIG. 5 is a side elevational view of the front pump plateshown in FIG. 1;

FIG. 6 is an end elevational view of the interior of the pump body withthe cylinder removed taken in the direction of arrows 6-6 of FIG. 1, ona reduced scale;

FIG. 7 is a right end elevational view of the pump shown in FIG. 1, on areduced scale;

FIG. 8 is a schematic vertical section of a constant displacement typeof pump showing a modified nozzle shut off valve in conjunction with anair control spring and a main pressure control and bypass spring with avalve controlling piston in the discharge chamber.

DETAILED DESCRIPTION OF THE INVENTION It will be understood that theabove drawings illustrate merely a preferred embodiment of the inventionand that other embodiments are contemplated within the scope of theclaims hereafter set forth.

Referring to the drawings, a variable capacity pump 11 is shown, FIGS.1, 2 and 7, including body 13 with removable cover 15.

Fluid inlets 17 and 19 are formed as a part of the body, FIG. 2, and maybe selectively used. One such inlet is closed by the plug 21, providingcommunication to chamber 23 upon the interior of said cover.

A cylinder is provided within the pump body which includes the uprightrear pump plate 25 having an annular exterior groove 27 formed therein,FIG. 1, adjacent the hardened metal shroud 29 secured to the rear pumpplate and extending outwardly thereof.

The cylinder has an upright front pump plate 31 which includes thelateral hub 33 having a bore 35 adapted to receive a power operated pumpshaft 37 which is connected to and drives the rotor 39, FIGS. 1 and 2.

Thrust cone 41 is formed upon the inner end of shaft 37 and is adaptedfor cooperative end thrust registry with the shroud 29.-

The rotor has nested within its opposite sides suitable rings 43 formechanically keeping the pump vanes 45 in contact with the bore ofstator slide 51. A series of and upon the opposite side, the deliverychamber 49.

Said stator is nested within a pump outer casing 52 and includes atopposite ends the extensions or guide plates 53 movable withincorresponding radial slots 55 fonned in the pump outer casing andsuitably sealed with respect thereto at 57.

One of the extensions or guide plates 53 forms with slot 55 a deliverychamber 59 adapted for connection with a discharge outlet as at 139,FIG. 2, for connection with a nozzle such as employed in an oil burner.

The chamber 59 includes a cut off valve opening which consists of thenozzle cut off valve seat 61 and a soft valve 63 mounted upon the slideextension 53 of the stator 51 and normally in registry with said seatfor closing off flow to the discharge passage 139.

Upon the opposite side of the body 13 there is provided the radial boss65 within which is positioned spring'retainer 69 which normally bearsupon the rear and front pump plates 25 and 31 with air release spring 67interposed between the stator slide 51 and said spring retainer.

The air release spring is a relatively weak spring adapted to yield atpressures in the range of between and 35 pounds per square inch. A muchstronger discharge pressure spring 71 is nested within the boss 65 andinterposed between the spring retainer and the body adapted to normallyresist relative outward movement of said spring retainer.

An adjustable screw nut 73 bears against the outer end of the dischargepressure spring 71 and threadedly receives adjusting screw 75 anchoredwith respect to seal plates 77 with screw seal 79 interposedtherebetween.

Referring to FIGS. 1 and 7, the pump body includes an elongated axialboss which tenninates in mounting flange 81. Seal cover 83 is aperturedto receive the pump shaft 37 and is secured to the outer face of flange81 and mounts an apertured disc-like seal 87 seated against the bodywith seal 87 gasket imposed.

A longitudinally adjustable and rotatable nose piece 89 has an axiallyextending annular seal flange 91 adapted for sealing has a laterallyextending seal flange 91 adapted for sealing registry throughout 360with the seal 87 with a suitable O ring 93 interposed between said nosepiece and shaft. Said nose piece is of carbon or other suitablematerial.

Seal drive 95 is mounted upon shaft 37 and secured thereto for rotationtherewith by the transverse pin 101. Seal spring 103 is interposed incompression between said seal drive and nose piece 89 normally urgingsaid nosepiece into cooperative sealing registry with seal 87.

Suitable drive means are employed between the seal drive and the nosepiece in the form of splines 99 between the corresponding registeringends of the seal drive and nose piece so that the nose piece rotateswith the drive shaft.

Since the compression spring 103 is biased against the seal drive due tothe pin 101,'said spring tends to urge the pump shaft 37 axially inwardand its end thrust is taken up with a minimum of friction due to theconical end 41 in registry with shroud 29.

Within the rear pump plate 25 in registry with its exterior annulargroove 27 are a pair of spaced axial ports 105 and 107 which communicatewith the fluid in chamber 23 upon the outside of the cylinder fordelivery into pumping chamber 47,49.

Diammetrically opposed bosses 109 and 111 FIG. 3 project from oppositesides of stator 51 so that in one position of said stator betweensaidend plates the boss 109 covers and blocks one of the ports 105 and107. Central portions of the stator upon its opposite sides are thinnedout to define upon the opposite faces thereof, slots or inlet passages 113 which communicate with the chamber 115 within the pump casing andlikewise communicate with one of the ports 105 and 107 in the rear pumpplate.

Upon the opposite side of the stator which is also thinned out, thereare provided a pair of slots or outlet passages 117, one of which isadapted for communication with one of the outlet ports 119 and 121formed in the front pump plate 31.

The latter outlet ports 119 and 121 communicate with annular groove 123in the outer face of the front pump plate, FIG. 5. This annular grooveis thus, delivering discharged fluids from the rotor chamber 49 forcommunication with the pair of angular grooves 125 and 127 formed in theinner surface of the pump casing, FIG. 6.

The one end of the said grooves have restricted axial passages 129formed through said body which communicate with the transverse bore 131shown in FIG. 7

across the end of the body. In the illustrative embodiment, the oppositeends of the bore'I31 are closed by a pair of plugs 133.

It is contemplated under some conditions that one of these plugs may beremoved and a return line provided for any excess fluids back to a fluidstorage sump.

The front pump plate 31 is in snug registry with the inner surface ofthe body corresponding to the grooves 125 and 127, to providecommunication from one of the said grooves to a corresponding inlet 135and passage 137, FIG. 2 within stator 51 for delivering pumped fluidsinto the discharge chamber 59.

With the soft valve 63 unseated, due to pressure build up within saidchamber, air in the first instance and later liquids are deliveredthrough the ported valve seat 61 into the outlet 139, FIGS. 1 and 2,which communicates with a corresponding passage 141 in the pump frontplate and thence to the bore 143 and into transverse passage 145, alsoshown in FIG. 7. Passage 145 is a discharge passage adapted forconnection to a burner nozzle, for illustration, of an oil burner or forany other discharge receiver. The other end of the passage 145 is closedby a plug 149, FIG. 7.

OPERATION It is one of the purposes of the present invention to providea means of discharging air at relative low pressure into the nozzleconduit 139, 141, 143 and 145 and into the fire box and at about thesame time, providing that when oil reaches the pump that the normaladjustable pressure will be generated. This is accomplished in thefollowing manner:

Flow of oil from the discharge chamber 49 of the pump to the nozzle isaccomplished by passing through a cut off valve opening which consistsof the seat 61 formed in the cylinder casing 52 through which projectsdischarge passage 139 in conjunction with the soft valve 63 on thestator slide 51.

As pressure under said slide within delivery chamber 59 builds up fromthe operation of the pump 39, it tends to lift the soft valve 63 awayfrom its seat, causing the valve to open. This movement is resisted fora short distance by a relatively weak spring referred to as air releasespring 69 on the opposite side of the slide for a distance of about0.015 inches.

The slide then strikes the'spring retainer 67 which is resting on thepump end plates 25 and 31 and further movement is controlled by theheavier adjustable spring referred to as discharge pressure spring 71,FIG.

When the pump first starts up, it is wetted with oil from assembly orits previous operation. The suction line and piping is substantiallyfilled with air. While the orifice in the burner nozzle forms asubstantial constriction, it could discharge air or gas to the fullvolume of the pump at relatively low pressure if it could get by thenozzle shut off valve 63-61.

In the past, this valve has always been closed by the full pressure ofthe main adjustable spring which is commonly set at 125 pounds. To pumpair to this pressure, even in a wetted pump, would require very closetolerances in the displacement used. In the present invention,therefore, the initial movement of the shut off valve for approximately0.015 inches is controlled by a far weaker spring 67 of approximately 25pounds pressure. This permits the valve to crack at about that pressureand discharge air out of the nozzle going through discharge passage 139.

However, when solid liquid reaches the pump and nozzle, further pressureis generated due to the inability of the nozzle to pass that volume ofliquid, and the slide has to move and overcome the pressure of the mainspring 71 in order to reachan equilibrium of volume with the pumpdischarge.

It is noted that in all cases, the shut off valve 63 is held against itsseat 61 by the relatively weak air release spring 67 which isnonadjustable. Heretofore, the valve was held on its seat by a springwhich could be adjusted from to 175 pounds operating pressure, and thesame valve was used for springs up to 300 pounds operating pressure ormore.

The valve, therefore, had to be relatively hard and capable of standingthe maximum pressure without permanent deformation. With the presentconstruction since the pressure is lighter and always uniform, a valvemost suitable for this pressure alone can be employed.

MODIFICATION The basic idea of an air release through the nozzle at lowpressure is equally applicable to the present constant displacement oilmotor pumps, such as shown in FIG. 8, which use a piston type of bypassvalve to bypass the surplus oil which is pumped but not used at thenozzle. These pumps cannot prime themselves, except on two pipe systemswhich are costly to install.

A bleed slot is used in the piston type of bypass valve which in a twopipe system permits air to return to the tank and in a single pipesystem to the suction side of the pump.

Referring to the schematic illustration, FIG. 8, of such a system, thereis provided a positive 'oil burner pump with a modified piston type ofbypass valve 169. It has no bleed slot and the cut off would have to beobtained by means of a centrifugal clutch or solenoid valve, either ofwhich has other desirable features.

In FIG. 8 there is illustrated a constant displacement type of pumpwhich includes in a single pipe system 151, a fixed capacity gear pump153 connected to a suitable pump drive shaft 155 within the pump housing157 having inlet 159 from a tank of liquid.

Said housing includes outlet 167 adapted for connection to a nozzle of aburner or for other purposes receiving fluids from delivery chamber'163'within the housing. The nozzle shut off valve seat 165, FIG. 8,communicates with the discharge passage 167 to such nozzle.

Nozzle shut off valve 169 has a body in the form of a piston which ismovable in a bore which corresponds to and merges with chamber 163. Saidvalve includes a soft valve 170 adapted nonnally for registry with seat165 closing off flow of pumped fluids to discharge passage 167.

The annular flange 171 forming a part of piston 169 is normally inregistry with such portion of the wall of the chamber as to close offthe outlet 172 to bypass conduit 173 in the housing.

The formed spring retainer 175 is nested within the bore which forms anextension of chamber 163 and extends up into the piston valve 169 and isheld in such position by the discharge pressure bypass spring 177.

Said retainer, flared at its outer end, is adapted for registry with thestop shoulder 179 in said housing. This end of the spring retainerengages the shoulder under the bias of bypass spring 177 after it hasclosed the bypass 173 by the movement of the valve 169 to a positionabove what is shown in FIG. 8. Due to the engagement of the retainerwith stop shoulder 179 the soft valve element 170 has not been fullyclosed against the seat 165, leaving a gap of about 0.015 inches.

This last movement of soft valve 170 is obtained by the much weaker aircontrol spring 185 which is interposed between the inner end of retainer175 and the shut off valve piston 169, thus forcing the valve againstthe seat 165. Here again the force is lighter and without adjustment, soa much more resilient valve can be safely used.

At the opposite end of the bypass spring 177 there is provided springretainer 181 under the control of the adjusting screw 183 threaded intosaid housing.

OPERATION The operation of the positive pump is as follows: When thepump starts up and the line is full of air and requires priming, it willbe pumping full capacity and can readily pump the low pressure needed toovercome an adequate orifice to accommodate the full volume at lowpressure.

However when solid liquid reaches the pump 153, and said nozzle,additional pressure is build up through the inadequacy of the smallnozzle orifice to handle this substantial volume of liquid, with theresult that the piston 169 is forced further outward and eventually mustovercome the pressure of the main adjustable spring 177 in order thatthe piston valve reach the bypass position shown in FIG. 8 and to, thus,stabilize the pressure fluid and with some of the fluid not flowingthrough the discharge passage returning via the bypass 173 back to thetank.

It will be seen that this construction permits both the variablecapacity and fixed capacity pumps, FIGS. 1 and 8, to be self-priming ona single pipe system by discharging the air through the nozzle where itcan do no harm. Not only does it eliminate the need for costly two pipesystems, but it also in most cases, eliminates the need for two stagepumps.

Having described my invention, reference should now be had to thefollowing claims.

I claim:

1. In a variable capacity pump having a body with a liquid inlet portand a discharge outlet adapted for connection to a nozzle;

a cylinder within the body formed by a hollow casing,

and front and rear pump plates secured thereto;

a pump stator slidably mounted in said cylinder engaging said pumpplates and having an cylindrical opening therethrough;

a rotor with radially movable vanes mounted in said opening with thevanes adapted to move over the boundary of said opening for a pumpaction, receiving liquid through a port in said rear pump plate anddischarging liquid through a port in said front plate;

the improvement comprising a drive shaft mounted and journalled in saidbody extending through said pump plates and secured to said rotor;

opposed extensions on said stator slidably movable respectively within aradial first slot extending through said casing;

and a radial second slot extending into said casing;

said second slot outwardly of one statorextension defining a dischargechamber adapted to receive pumped fluids;

there being a cut off valve opening in said casing adapted forconnection to said discharge outlet;

said cut off valve opening including a seat in said chamber, and a softvalve on one stator extension normally in registry with said seat;

a spring retainer within said pump body normally spaced radially outwardof the other stator extension and supported upon said pump plates;

an air release spring interposed between said retainer and said statorextension, yieldably resisting radial outward movement thereof;

and a discharge pressure spring coaxial of and interposed between saidretainer and said body normally holding said retainer during initialmovement of said stator towards and into engagement with said retainer,so that initial low pressure air delivered to said chamber lifts thesoft valve from said seat for delivery to said nozzle;

solid liquid subsequently pumped to said chamber of progressivelyincreasing pressure causing the stator to move further radially outwardagainst the action of said discharge pressure spring, further openingsaid valve to reach an equilibrium of volume of pumped liquid deliveredto 'said nozzle.

2. In the pump of claim 1, said air release spring being relatively-weakresponding to pressures in the range of 5 to 35 pounds per square inch,said discharge pressure spring being relatively strong responding toliquid pressure in the range of 50 to 200 pounds per square inch.

3. In the pump of claim 1, said pump body having a chamber looselyenclosing said cylinder defining an annular space around said cylindercommunicating with said inlet port; a cover on said body closing saidchamber; there being an annular groove on said rear pump plate, inregistry with the rear pump plate port.

4. In the pump of claim 3,-said stator being chamfered upon its oppositefaces defining inlet and outlet passages; said inlet passagescommunicating with said rear pump plate port for delivery of fluid tothe intake side of said rotor.

5. In the pump of claim 4, said outlet passages receiving pumped fluidfrom the discharge side of said rotor for delivery to said front plateport and to said discharge chamber.

6. In the pump of claim 5, there being a second axial port in the rearand front pump plates spaced from its respective first port; said secondport in said rear pump plate communicating with its annular groove andadapted to communicate with said stator inlet passages; said second portin said front pump plate adapted for communicating with said statoroutlet passages and said discharge chamber; said stator adapted to bereversed face to face for respective communication of the inlet passageswith the second port in said rear pump plate and communication of theoutlet passages with the second port in said front pump plate; therebeing diammetrically opposed axial bosses projecting from the respectiveopposite sides of said stator; said bosses selectively closing one portin said rear pump plate and one port in said front pump plate, wherebyupon rotation of said rotor in the reverse direction, all that isrequired is to reverse the position of said stator face to face.

7. In the pump of claim 5, conduit means for delivering pumped fluidsfrom said front plate port to said discharge chamber, said conduit meansincluding a passage in said stator outletting to said discharge chamber,and a slot upon the inner face of said body adjacent said pump frontplate in registry with the front pump plate port and with said statorpassage.

8. In the pump of claim 7, there being an annular slot in the outer faceof said front pump plate in registry with its port and communicatingwith said body slot.

9. In the pump of claim 7, there being a fluid return axial port in saidbody inner face in registry with said inner face slot; and a restrictedfluid return outlet on said pump body connected to said body portadapted for connection to a fluid storage tank for bypassingof pressurefluid.

10. In the pump of claim 1, a radial boss on said body having a borereceiving said spring retainer and said discharge pressure spring; anadjusting screw nut in said bore retainingly engaging the outer end ofsaid discharge pressure spring; and a discharge pressure adjustment boltrotatively anchored in said boss and threaded into said nut.

11. In the pump of claim 1, a hardened steel shroud mounted over therear pump plate; the inner end of said drive shaft having a conical endin axial end through engagement with said shroud. I

12. In the pump of claim 11, an axial boss on said body receiving saiddrive shaft; an apertured seal cover on the outer end of said bossreceiving said shaft;'an -an-' nular apertured seal receiving said shaftseated on the outer end of said boss and anchored by said seal cover;

- from said nosepiece, secured upon said shaft and rotatable therewith;a compression spring between said seal drive and seal face nose piece;and drive means between said seal drive and nose piece, said hose piecebeing longitudinally movable on said shaft; the thrust of said springupon said nose piece tending to slide the drive shaft inwardly biasingthe shaft conical end against said shroud minimizing friction due to thethrust from said spring.

13. In the pump of claim 1, an axial boss on said body receiving saiddrive shaft; an apertured seal cover on the outer end of said bossreceiving said shaft; an annular apertured seal receiving saidshaftseated on the outer end of said boss and anchored by said sealcover; a rotative seal'face nose piece within said boss in engagement onone side with said seal; a seal drive secured upon said shaft androtatable therewith; a compression spring between said seal drive andsaid seal face nose piece; and a drive means between said seal drive andnose piece, said nose piece being longitudinally movable on said shaft.

1 4. In the pump of claim 13, and an annular flange on said one side ofsaid nose piece in continuous engagement with said seal throughout 360.

15. In the pump of claim 13, said seal drive means between said sealdrive and nose piece being a series of splines.

1. In a variable capacity pump having a body with a liquid inlet portand a discharge outlet adapted for connection to a nozzle; a cylinderwithin the body formed by a hollow casing, and front and rear pumpplates secured thereto; a pump stator slidably mounted in said cylinderengaging said pump plates and having an cylindrical openingtherethrough; a rotor with radially movable vanes mounted in saidopening with the vanes adapted to move over the boundary of said openingfor a pumping action, receiving liquid through a port in said rear pumpplate and discharging liquid through a port in said front plate; theimprovement comprising a drive shaft mounted and journalled in said bodyextending through said pump plates and secured to said rotor; opposedextensions on said stator slidably movable respectively within a radialfirst slot extending through said casing; and a radial second slotextending into said casing; said second slot outwardly of one statorextension defining a discharge chamber adapted to receive pumped fluids;there being a cut off valve opening in said casing adapted forconnection to said discharge outlet; said cut off valve openingincluding a seat in said chamber, and a soft valve on one statorextension normally in registry with said seat; a spring retainer withinsaid pump body normally spaced radially outward of the other statorextension and supported upon said pump plates; an air release springinterposed between said retainer and said stator extension, yieldablyresisting radial outward movement thereof; and a discharge pressurespring coaxial of and interposed between said retainer and said bodynormally holding said retainer during initial movement of said statortowards and into engagement with said retainer, so that initial lowpressure air delivered to said chamber lifts the soft valve from saidseat for delivery to said nozzle; solid liquid subsequently pumped tosaid chamber of progressively increasing pressure causing the stator tomove further radially outward against the action of said dischargepressure spring, further opening said valve to reach an equilibrium ofvolume of pumped liquid delivered to said nozzle.
 2. In the pump ofclaim 1, said air release spring being relatively weak responding topressures in the range of 5 to 35 pounds per square inch, said dischargepressure spring being relatively strong responding to liquid pressure inthe range of 50 to 200 pounds per square inch.
 3. In the pump of claim1, said pump body having a chamber loosely enclosing said cylinderdefining an annular space around said cylinder communicating with saidinlet port; a cover on said body closing said chamber; there being anannular groove on said rear pump plate, in registry with the rear pumpplate port.
 4. In the pump of claim 3, said stator being chamfered uponits opposite faces defining inlet and outlet passages; said inletpassages communicating with said rear pump plate port for delivery offluid to the intake side of said rotor.
 5. In the pump of claim 4, saidoutlet passages receiving pumped fluid from the discharge side of saidrotor for delivery to said front plate port and to Said dischargechamber.
 6. In the pump of claim 5, there being a second axial port inthe rear and front pump plates spaced from its respective first port;said second port in said rear pump plate communicating with its annulargroove and adapted to communicate with said stator inlet passages; saidsecond port in said front pump plate adapted for communicating with saidstator outlet passages and said discharge chamber; said stator adaptedto be reversed face to face for respective communication of the inletpassages with the second port in said rear pump plate and communicationof the outlet passages with the second port in said front pump plate;there being diammetrically opposed axial bosses projecting from therespective opposite sides of said stator; said bosses selectivelyclosing one port in said rear pump plate and one port in said front pumpplate, whereby upon rotation of said rotor in the reverse direction, allthat is required is to reverse the position of said stator face to face.7. In the pump of claim 5, conduit means for delivering pumped fluidsfrom said front plate port to said discharge chamber, said conduit meansincluding a passage in said stator outletting to said discharge chamber,and a slot upon the inner face of said body adjacent said pump frontplate in registry with the front pump plate port and with said statorpassage.
 8. In the pump of claim 7, there being an annular slot in theouter face of said front pump plate in registry with its port andcommunicating with said body slot.
 9. In the pump of claim 7, therebeing a fluid return axial port in said body inner face in registry withsaid inner face slot; and a restricted fluid return outlet on said pumpbody connected to said body port adapted for connection to a fluidstorage tank for the bypassing of pressure fluid.
 10. In the pump ofclaim 1, a radial boss on said body having a bore receiving said springretainer and said discharge pressure spring; an adjusting screw nut insaid bore retainingly engaging the outer end of said discharge pressurespring; and a discharge pressure adjustment bolt rotatively anchored insaid boss and threaded into said nut.
 11. In the pump of claim 1, ahardened steel shroud mounted over the rear pump plate; the inner end ofsaid drive shaft having a conical end in axial end thrust engagementwith said shroud.
 12. In the pump of claim 11, an axial boss on saidbody receiving said drive shaft; an apertured seal cover on the outerend of said boss receiving said shaft; an annular apertured sealreceiving said shaft seated on the outer end of said boss and anchoredby said seal cover; a rotative seal face nose piece within said boss inengagement on one side with said seal; a seal drive spaced from saidnose piece, secured upon said shaft and rotatable therewith; acompression spring between said seal drive and seal face nose piece; anddrive means between said seal drive and nose piece, said nose piecebeing longitudinally movable on said shaft; the thrust of said springupon said nose piece tending to slide the drive shaft inwardly biasingthe shaft conical end against said shroud minimizing friction due to thethrust from said spring.
 13. In the pump of claim 1, an axial boss onsaid body receiving said drive shaft; an apertured seal cover on theouter end of said boss receiving said shaft; an annular apertured sealreceiving said shaft seated on the outer end of said boss and anchoredby said seal cover; a rotative seal face nose piece within said boss inengagement on one side with said seal; a seal drive secured upon saidshaft and rotatable therewith; a compression spring between said sealdrive and said seal face nose piece; and a drive means between said sealdrive and nose piece, said nose piece being longitudinally movable onsaid shaft.
 14. In the pump of claim 13, and an annular flange on saidone side of said nose piece in continuous engagement with said sealthroughout 360*.
 15. In the pump of claim 13, said seal drive meansbetween said seal drive and nose piece being a series of splines.